Alkylbenzene sulfonate production via n-olefin dimerization



United States Patent 3,238,249 ALKYLBENZENE SULFONATE PRODUCTION VIAN-OLEFIN DIMERIZATION Stanley B. Mirviss, Westfield, James H. McAteer,Cranford, and Joseph F. Nelson, Westfield, N.J., assignors to EssoResearch and Engineering Company, a corporation of Delaware N0 Drawing.Filed Sept. 23, 1960, Ser. No. 57,885 6 Claims. (Cl. 260505) The presentinvention relates to improved biodegradable alkyl benzene detergents andto processes for their preparation. More particularly, this inventionrelates to an improved detergent prepared by dimerizing a C -Cpredominantly straight chain olefin in the presence of an aluminum alkylor a dialkyl aluminum halide catalyst, alkylating benzene therewith andsulfonating the resultant alkyl benzene to obtain the final productdetergent. Most particularly this invention relates to utilizing a C -Cpredominantly straight chain alpha olefin stream from steam cracking asthe feed to the process and to utilizing mild conditions in alkylation.

According to the present invention it has now been discovered thatbiodegradable detergents having excellent washing properties may beobtained by the process of this invention. A C -C predominantly straightchain olefin is dimerized in the presence of an alkyl aluminum catalystto obtain an olefin predominantly of the following structure.

wherein R is a predominantly straight chain alkyl group of from 3 to 6,e.g., 4 carbon atoms, R is a predominantly straight chain alkyl group offrom 5 to 8, e.g., 7 carbon atoms, and the extent of the branching ofthe alkyl groups is such that on the average less than 1.0, preferablyless than 0.6 methyl group, in addition to the two terminal methylgroups, are contained in R and R. It should be noted that less than 10%,preferably less than 5%, of the branches R and R are higher alkylgroups, e.g., ethyl groups, rather than methyl groups. This olefin isthen used to alkylate benzene to obtain an alkyl benzene havingprimarily (e.g., above 75%, preferably greater than 85) the followingstructure:

wherein R and R are as above described and wherein again the extent ofthe branching of the alkyl groups is such that on the average less than1.0, preferably less than 0.6 methyl groups, in addition to the terminalmethyl groups, are contained in R and R. Thus, the olefin adds veryselectively to the benzene through the tertiary carbon atom of theolefin. The small amount of other material formed is due mainly toisomerization of the olefin double bond occurring during alkylation anddimerization.

As is well known the two prime problems present today in detergentmanufacture are the reduced washing properties obtained where detergentsare used in soft water areas, and the problem of the poorbiodegradability of conventional detergents, (i.e., capacity -to beremoved in sewage disposal plants). With respect to the former of theseproblems, it is known that the washing efficiency of conventional alkylbenzene detergents obtained from tetrapropylene is reduced byapproximately 20% in soft water areas. This is a very serious problem inview of the fact that in the United States, for example, more than 50%Patented Mar. 1, 1966 "ice of the population lives in these soft waterareas, i.e., areas where the water contains 0 to 4.7 grains of calciumand magnesium salts per gallon.

With respect to the latter problem, the removal of detergent materialsin sewage disposed plants so that the effluent from these plants doesnot introduce these active materials into rivers and streams isextremely important. Thus, severe fouling and foaming problems have beenencountered in many countries due to the lack of biode gradability ofconventional commercial detergents. It has now been discovered that thepresent material solves both of these problems and is easily and cheaplyprepared.

Suitable feed stocks for use in the present invention process are C -Cpredominantly straight chain monoolefin streams obtained from commercialprocesses such as both mild and severe stream cracking. Both the entireC -C stream and selected fractions from this stream, e.g., a C stream,are preferred feed stocks. The extent of branching of the olefins inthese feed stocks (on other than the ethylenic carbon atoms, i.e., thecarbon atoms attached to the double bond) must be on the average lessthan 0.5, preferably less than 0.3 methyl groups per molecule. By methylgroups per molecule it is intended to include both methyl groups as suchand other alkyl group branches. It should be noted that those olefinspresent in the feed stock which contain branches on either of theethylenic carbon atoms do not react in the dimerization reaction andhence, of course, may be present in the feed wiithout deleterious effecton the dimer product. Other olefin containing feed stocks may also beutilized so long as they meet the above described requirement as to theextent of branching permissible. Paraffins and aromatics may be presentin these feed stocks since they do not react in the dimerizationreaction. Where these feed stocks contain diolefins and acetylenes, in apreferred embodiment these materials are removed by known methods suchas extraction, hydrogenation, etc., to increase the purity of the dimerproduct obtained.

In one embodiment preferred C -C feed stocks are obtained from the lowseverity steam cracking of wax, petrolatum or a paraffinic gas oil.Temperatures of 10004200 F. and conversions to C minus of 5 to 15 wt.percent are used to produce mainly C -C monoolefins. It should be notedthat in a preferred embodiment these olefins are obtained from lowconversion steam cracking processes conducted in the vapor phase. Theamount of steam utilized is not critical, in general 50 95 mol percentsteam based on total feed plus steam being used. The olefins boiling inthe C -C range contain above wt. percent, preferably about wt. percent,straight chain olefins. Additionally these olefins are above 80 wt.percent alpha olefins. Although non-alpha olefins can be easilyisomerized to alpha olefins during dimerization by having an additionalcatalyst present (as will be described) still some undesirableisomerization is obtained in such a modified dimerization process andtherefore predominantly alpha olefin feed stocks are preferred.

In another embodiment preferred C C feed stocks are obtained by liquidphase thermal cracking a paraffinic feed stock of the type abovedescribed at temperatures of 800 F. to 1000 F., and conversions of freshfeed to lighter boiling products of 20 to wt. percent. By such a process40 to 60% of predominantly straight chain olefins are obtained, theremainder, being paraffins and small amounts of diolefins. If desired,the olefins may be dimerized directly from the parafiins.

In another embodiment preferred C C feed stocks are obtained from thewidely commercially used high conversion steam cracking of gas oils toproduce commercially desirable C -C olefins and diolefins as Well ashigher boiling materials. Temperatures of about 1250-1500 F., amounts ofsteam as above described and residence times to obtain conversion to Cminus of 20 to 80 wt. percent are used in this process. The olefinsboiling in the C C range from the high conversion steam cracking processmay be treated by extraction to remove aromatics, if desired, or may beused without such a removal of aromatics. C -C cuts obtained from thehigh severity cracking of various gas oils or naphthas contain generallyabove 20 Wt. percent straight chain olefins and certain fractionsobtained from paraflinic gas oils may contain as much as 60 Wt. percentstraight chain olefins, or even 80 Wt. percent straight chain olefins.The amount of benzene present in a C -C cut is, e.g., to 30 wt. percent.As previously mentioned in one embodiment the benzene present (whichboils in the C olefin boiling range) in the feed stream is not remove-dby extraction prior to dimerization since it is advantageous in thisreaction, and in the following alkylation it supplies part of the feedbenzene required.

It should be noted that the C -C olefinic streams from seam crackingabove described are byproducts in the production of other more valuablematerials and that these streams are ordinarily used only for their fuelvalue in gasoline. It is of course also contemplated that particularolefinic streams as above described, after conventional removal of morevaluable components, e.g., aromatics, diolefins, etc., may be utilized.These feed streams are extremely inexpensive feed stocks for the presentprocess.

In a final embodiment preferred C -C feed stocks are obtained by anethylene growth process in the presence of aluminum alkyls. In thisprocess, for example, ethylene is reacted with an aluminum alkyl, e.g.,aluminum triethyl, at temperatures of 160 to 350 F. and pressures of 500to 5000 p.s.i.a. to obtain C C aluminum trialkyls and these higheraluminum trialkyls are then reacted with an olefin to displace thehigher alkyls and thus form C C olefins. A general discussion of thisprocess is found in US. Patent 2,781,410. The desired C -C straightchain olefin feed stocks for the present invention are of course lessvaluable than the higher straight chain olefin main product.

Dimerization is carried out utilizing an aluminum trialkyl or dialkylaluminum chloride catalyst preferably an aluminum trialkyl catalyst.Preferably the alkyl groups in these catalysts are C -C alkyl groups.The catalyst is used in quantities of from 0.5 to 20 wt. percent,preferably 2 to 10 wt. percent, e.g., 10 Wt. percent, based on theolefin in the feed. Preferred catalysts are aluminum trialkyl catalystsprepared from the feed olefins to be dimerized. Such catalysts, ofcourse, do not contaminate the desired dimer product with differentdimer materials formed from the catalyst alkyl groups. Other preferredcatalysts are aluminum trialkyls branched at the beta carbon atoms ofthe alkyl groups, e.g., aluminum triisobutyl. These aluminum trialkylsdo not react in the dimerization process and hence also do notcontaminate the product.

An additional different catalyst may be employed if desired,particularly where the feed stock contains in addition to alpha olefinsinternally double bonded straight chain olefins. Thus, in such anembodiment a concurrent isomerization of these internally double bondedolefins is obtained so that the desired final product from the processis obtained. Suitable additional catalysts are nickel, cobalt,palladium, platinum and the like. Although these catalysts can besupported on inert supports such as alumina, it is preferred to utilizeunsupported catalysts. The amount of this additional catalyst utilizedshould be in the range of 0.1 to 10, preferably 0.5 to 5, e.g., 1 wt.percent, based on the aluminum alkyl catalyst.

Additionally an inert solvent may be used such as a C -C acyclic orcyclic paraffin, e.g., normal pentane, hexane, heptane, etc. and isomersof these materials, and cyclopentane, cycloheptane, etc. Chlorobenzene,benzene and toluene may also be used. Where a solvent is used it ispreferred to utilize a feed stock containing the diluent material.Particularly such a preferred diluent is an aromatic hydrocarbon whichis to be a coreactant in the next step.

The dimerization reaction is carried out at temperatures in the range of80 to 300 C., preferably 110 to 250 C., e.g. 190 C., pressures in therange of atmospheric pressure to 200 atmospheres, e.g., 170 atmospheres,utilizing reaction times in the range of 0.5 to 25 hours, preferably 1to 20 hours, e.g., 4 hours. Preferably the reaction is carried out in aliquid phase. Following reaction, the dimer is separated, e.g., bydistillation, from unreacted olefin and from aluminum alkyl material(and from diluent if a diluent is used). Alternatively the entiremixture after separation of aluminum alkyl material may be supplied tothe alkylation step. The separated aluminum alkyls are, of course,preferably recycled to the reaction zone for reuse in dimerization.

Alkylation is carried out utilizing benzene or less preferably toluene,in the presence of a Friedel-Crafts type catalyst at temperatures in therange of 10 to C., e.g. 10 C. Preferred catalysts are, for example, AlClHF, BF and AlBr polyphosphoric acid, H and aluminum chloride hydrocarboncomplexes.

It is generally desirable to maintain in the reaction mixture a volumeratio of aromatic hydrocarbon to olefin of at least 3:1, e.g., 5:1,although ratios up to 20:1 may be used.

In the case of utilizing catalysts such as AlCl BF etc. preferably AlClit is preferred to utilize in one embodiment mild conditions of 5 to 20C., e.g., 10 C., and in another embodiment conventional conditions of 20to 60 C., e.g., 45 C. In both of these embodiments weight ratios ofolefin to catalyst are in the range of 30:1 to 10:1, e.g., 20:1.Additionally in the case of the use of aluminum chloride an activatorsuch as HCl may be added in an amount of from 15 to 40 wt. percent,e.g., 20 Wt. percent, based on aluminum chloride.

In utilizing the liquid hydrogen fluoride catalyst it is preferred touse an acid to hydrocarbon reactants volume ratio of 0.1:1 to 1.021,e.g. 0.3:1 and temperatures in the range of 0 to 15 C., e.g., 10 C. Theconcentration of this catalyst may range from to HP by Weight, its watercontent being maintained very low, e.g., no higher than 1 or 2% byweight, the remainder being dissolved hydrocarbon material.

The alkylated aromatic fraction is recovered from the alkylationreaction mass and is sulfonated in known manner, e.g., by contact Withan excess of concentrated sulfuric acid, oleum, ClSO H, sulfur trioxide,etc. The sulfonation may be carried out at temperatures up to 60 C.,preferably for oleum 15 C. to 60 C., e.g. 50 C. The acid concentrationis preferably at least 97%. Acid up to 100% concentration and preferablyoleum, containing up to, e.g., 20 wt. percent S0 or higher, may beemployed. With higher acid concentration, lower reaction times arerequired, e.g., about 3 to 4 hours with 98% acid, about 2 hours with100% acid, and preferably 0.5 to 1 hour, e.g., 0.7 hour, with oleum.Volume ratios of sulfuric acid to hydrocarbon may range from 0.8:1 to1.25:1, a 1:1 ratio being suitable. The larger the ratio, the moreinorganic sulfate Will be present in the product followingneutralization. In many cases, the inorganic sulfate is a desirableconstituent of the finished detergent composition.

The sulfonation product mixture may be separated by layering to removepart of the excess spent acid before neutralizing or may be neutralizeddirectly. When neutralized, the sulfonic acids are thus converted tosulfonic acid salts and the excess sulfuric acid into sulfate. Theneutralization may be carried out with any base or basic- Example 1 Run1.-A .3-liter bomb was charged with 500 g. of hexane-1 and :50 g. ofAl(nahexyl) wt. percent on olefin) and the bomb was heated at 185190 C.for 17 hours and then cooled. The contents were emptied and distilled.The products consisted of 356 g. of C olefin which was approximately 82%Type III olefin, 8% Type II (trans) olefin, less than 1% of Type Iolefin according to infrared analysis, and the remainder being Type IVolefin. This infrared analysis was based on the spectra fractionation.The yield of alkylate was found to be 80 volume percent and was 99% pureC alkylate. It should be noted that tetrapropylene prepared bypolymerizing propylene in the presence of phosphoric acid under similarconditions gives only a 72 volume percent yield.

Run 3.--The alkylate prepared as described in Run 2 was sulfonated with20% oleum at 15 to 60 C. by adding the oleum to the alkylate. The weightratio of oleum to hydrocarbon was 1.4:1 and the materials were reactedfor 45 minutes. Following reaction, the sulfonation product mixture wasneutralized to a pH of 7 with aqueous sodium hydroxide to obtain thesodium salts of the sulfonic acids admixed with sulfates produced fromexcess spent sulfuric acid. The neutralization was carried out attemperatures of about 45 C. utilizing a reaction time of about 15minutes.

Example 2 The detergent material prepared as above described was testedfor washing properties in dishwashin-g and in cotton laundering testsalong with a conventional detergent prepared from tetrapropylene.

TABLE "1.DISHWASHING TEST a A detergent consisting of the sodiumsulfonate of dodecyl (tetrapropyl) benzene.

for C olefins adjusted to C olefins. The non-type III C olefins arisefrom isomerization of the C Type III olefin, Z-nbutyl-octene-l. Itshould be noted that in general only Type I and II olefins will notproduce the desired alkyl benzene structure on alkylation. Also 92 g. ofhexene-l 'was recovered. The remaining product was 86 g. of alkylaluminum compounds which had a composition corresponding to 90% Al(C and10% Al(C The alkyl aluminum residue from the distillation can be reusedin dimerization. The material balance was 97 Wt. percent and the losseswere found to be only hexene-l occurring during distillation and ventingthe bomb of pressure after the reaction was completed. Thus 71% of thehexene-l charged was converted to C olefin, 18.5% of the hexene-l wasunreacted, and 7% was converted to C alkyl aluminum compounds.

Run 2.-The C olefin was then used to alkylate benzene and AlCl in theconventional manner to form the dodecylbenzene, consisting essentiallyof 2-phenyl-2-nbutyl-octane. The C olefin as prepared above was used toalkylate benzene in a laboratory glass stirred reactor using a 5:1volume ratio of benzene to olefin and using 5 wt. percent of aluminumchloride based on olefin as the catalyst. Benzene was run into thereaction flask at room temperature and HCl was then supplied to saidflask. The glass reactor was then heated to 45-50 C. and /a of the totalcatalyst was added. Olefin addition was begun from a funnel, and when /3was added in 15 minutes, olefin addition was temporarily discontinuedand a further of the catalyst was added. A second /3 of the olefin wasthen added in another 15 minute period. A final of the catalyst was thenadded and complete addition of the final A of olefin was made overanother 15 minute period. The reactor was stirred for an additional 15minutes (total time 1 hour). The reactor was cooled to room temperatureand the contents were transferred to a separatory funnel. The layerswere allowed to separate while a hydrocarbon layer was recovered. Thislayer was then washed with water and dilute carbonate and then finallywith water. The hydrocarbon product after excess benzene was strippedoff was worked up by As can be seen the experimental detergent is muchbetter in the runs marked with an asterisk, i.e. at low concentrationsand in soft water.

TABLE 2.-COTTON LAUNDERING TEST [Terg-O-Torneter] B U.S. TestingCorporation cloth-dry and dirty both sides. b Test fabrics CompanyCloth-oily and dirty one side.

The experimental and the commercial detergent are fully equivalent inthe heavy duty cotton laundering test. Thus, the fully biodegradablenature of the present detergent is obtained without detriment.

It is to be understood that this invention is not limited to thespecific examples, which have been offered merely as illustrations, andthat modifications may be made without departing from the spirit of thisinvention.

What is claimed is:

1. A process for preparing biodegradable alkylbenzene detergents whichcomprises selecting a C to C predominantly straight chain alpha olefinstream containing on the non-ethylenic carbon atoms, on the average lessthan 0.5 methyl groups in side chains, dimerizing the predominantlystraight chain alpha C to C olefins in the presence of a catalystconsisting essentially of an alumina alkyl at temperatures in the rangeof to 300 C., pressures in the range of atmospheric pressure to 200atmospheres and for reaction times in the range of 0.5 to 25 hours,separating olefin dimer from the reaction mixture, reacting benzene withthe resultant olefin dimer under active alkylating conditions to producealkylbenzene at least 75% of which having the structure wherein R is apredominantly straight chain alkyl group of from 3 to 6 carbon atoms, Ris a predominantly straight chain alkyl group of from to 8 carbon atomsand the extent of branching of the alkyl groups R and R is such that onthe average less than 1, preferably less than 0.6 methyl groups, inaddition to the 2 terminal methyl groups is contained in R and R,contacting said alkylbenzenes with an active sulfonating agent attemperatures of about to 60 C. and neutralizing the reaction productwith a basic aqueous solution at temperatures of from to 70 C.

2. A process according to claim 1 wherein the C to C straight chainolefin stream is obtained by steam cracking a gas oil at highconversion.

3. A process according to claim 2 wherein the C to C fraction from steamcracking is treated to remove the acetylenes and diolefins prior tobeing fed to the dimerization step.

4. A process according to claim 2 wherein the C to C fraction from steamcracking is extracted to remove aromatics prior to being fed to thedimerization step.

5. A process according to claim 1 wherein the C to C straight chainolefin stream is obtained by steam cracking of a paraffinic gas oilfeedstock at temperatures in the range of 1000 to 1200 F. utilizingconversions to C in the range of 5 to 15 wt. percent.

6. A process for preparing an al'kylbenzene sulfonate detergent materialwhich comprises dimerizing a stream of C to C predominantly straightchain alpha monoolefins containing on the non-ethylenic carbon atoms, onthe average less than 0.5 methyl group in side chains, at temperature inthe range of 150 to 200 C., at pressures in the range of atmospheric to200 atmospheres, utilizing reaction times of 1 to 20 hours, in thepresence of 2.0 to 10.0 wt. percent based upon the olefin in the feed,of a catalyst consisting essentially of Al(n -hexyl) separating olefindimers from the reaction mixture, reacting benzene with said olefindimers at temperatures of 20 to C., in the presence of an aluminumchloride catalyst using ratios of benzene to olefin dimers of about 3:1to 20:1, sulfonating the resulting alkylated benzene with oleum attemperatures of about 15 to C. and neutralizing the resultant reactionproduct with a basic aqueous solution at temperatures of about 20 to C.to obtain an alkyl benzene sulfonate.

References Cited by the Examiner UNITED STATES PATENTS Horeczy 2605052,612,531 9/1952 2,622,113 12/ 1952 Hervert 260-505 2,781,410 2/1957Biegler et al. 260683.15 2,796,429 6/ 1957 Kreps et a1 260-505 2,813,91711/1957 Sharrah 260-505 2,871,254 1/1959 HoOg et al. -2. 260-4052,897,156 7/1959 Lewis 260505 2,984,691 5/1961 Fotis 260-671 X 3,009,97211/1961 Johnson 260505 FOREIGN PATENTS 539,281 9/ 1941 Great Britain.

742,642 12/ 1955 Great Britain.

775,384 5 1957 Great Britain.

922,014 3/ 1963 Great Britain.

OTHER REFERENCES Hammerton, J. Appl. Chem., vol. 5, Sept. 1955, p. 522.Pot-olovskiy et al., Khimiya i Teknologiya Topliv i Masel, 1958, Nr. 6,pp. 3341, U.S.S.R.

LORRAINE A. WEINBERGER, Primary Examiner.

CHARLES B. PARKER, LEON ZITVER, Examiners.

1. A PROCESS FOR PREPARING BIODEGRADABLE ALKYLBENZENE DETERGENTS WHICHCOMPRISES SELECTING A C5 TO C6 PREDOMINANTLY STRAIGHT CHAIN ALPHAOLEFINSTREAM CONTAINING ON THE NON-ETHYLENIC CARBON ATOMS, ON THEAVERAGE LESS THAN 0.5 METHYL GROUPS IN SIDE CHAINS, DIMERIZING THEPREDOMINANTLY STRAIGHT CHAINALPHA C5 TO C6 OLEFINS IN THE PRESENCE OF ACATALYST CONSISTING ESSENTIALLY OF AN ALUMINA ALKYL AT TEMPERATURES INTHE RANGE OF 80 TO 300*C., PRESSURES IN THE RANGE OF ATMOSPHERICPRESSURE TO 200 ATMOSPHERES AND FOR REACTION TIMES IN THE RANGE OF 0.5TO 25 HOURS, SEPARATING OLEFIN DIMER FROM THE REACTION MIXTURE, REACTINGBENZENE WITH THE RESULTANT OLEFIN DIMER UNDER ACTIVE ALKYLATINGCONDITIONS TO PRODUCE ALKYLBENZENE AT LEAST 75% OF WHICH HAVING THESTRUCTURE